1. Field of the Invention
The present invention relates to an optical recording medium, specifically to an optical recording medium which enables writing on the surface thereof with a writing tool or a thermal transfer type printer.
2. Description of the Related Art
For read-only type optical recording media which have widely come into general use at present, such as a compact disc (hereinafter abbreviated as CD), a laser disc (hereinafter abbreviated as LD) and a digital video disc (hereinafter abbreviated as DVD), a substrate having information is produced by an injection molding method based on an original substrate usually called a stamper. This method makes it possible to produce media having the same information at a low cost in large quantities but is not suited for producing a small amount of media since the stamper is very expensive. An advance to an information-oriented society is accompanied with intensive requirements for higher density recording media than magnetic recording media. Accordingly, information recording media suited for production in small quantities or optical recording media for allowing users to freely record and preserve data have been developed.
Optical recording media can be divided into two kinds; a recordable type capable of recording and reproducing information, and an erasable type capable of erasing data after recording. Among them, a recordable type compact disc having a single substrate structure is called CD-R, and since it is compatible with an ordinary read-only CD, users thereof are gradually increasing. Since users of this CD-R write data after purchasing a medium having no data, it has to be found by any means what information is recorded on the medium.
Further, a recordable type optical recording medium called DVD-R which is compatible with a DVD has been put into the market in recent years. With respect to this, it has to be found by any means what information is recorded on the medium as is the case with a CD-R.
In general, a method of writing on a surface by hand using an oil base felt pen is employed as a method for showing a title. However, when the media are sold to end-users after inputting data into a CD-R, handwriting is not preferred. On the other hand, a method in which labels of paper and film are stuck as is the case with a floppy disc has the advantage that finely designed characters and pictures can be printed by a printer. However, when characters have to be written on the whole surface of a disc, a doughnut-shaped label having a large area has to be used, and it is very difficult to stick the label thereon while adjusting the position. Further, when a label is about to peel off, there is a fear that the label may peel off in the equipment to cause troubles. Accordingly, different methods have been desired.